Rossby waves mediate impacts of tropical oceans on west Antarctic atmospheric circulation in austral winter

Xichen Li, David M. Holland, Edwin P. Gerber, Changhyun Yoo

Research output: Contribution to journalArticle

Abstract

Recent studies link climate change around Antarctica to the sea surface temperature of tropical oceans, with teleconnections from the Pacific, Atlantic, and Indian Oceans making different contributions to Antarctic climate. In this study, the impacts of each ocean basin on the wintertime Southern Hemisphere circulation are identified by comparing simulation results using a comprehensive atmospheric model, an idealized dynamical core model, and a theoretical Rossby wave model. The results herein show that tropical Atlantic Ocean warming, Indian Ocean warming, and eastern Pacific cooling are all able to deepen the Amundsen Sea low located adjacent to West Antarctica, while western Pacific warming increases the pressure to the west of the international date line, encompassing the Ross Sea and regions south of the Tasman Sea. In austral winter, these tropical ocean basins work together linearly to modulate the atmospheric circulation around West Antarctica. Further analyses indicate that these teleconnections critically depend on stationary Rossby wave dynamics and are thus sensitive to the background flow, particularly the subtropical/midlatitude jet. Near these jets, wind shear is amplified, which strengthens the generation of Rossby waves. On the other hand, near the edges of the jets the meridional gradient of the absolute vorticity is also enhanced. As a consequence of the Rossby wave dispersion relationship, the jet edge may reflect stationary Rossby wave trains, serving as a waveguide. The simulation results not only identify the relative roles of each of the tropical ocean basins in the tropical-Antarctica teleconnection, but also suggest that a deeper understanding of teleconnections requires a better estimation of the atmospheric jet structures.

Original languageEnglish (US)
Pages (from-to)8151-8164
Number of pages14
JournalJournal of Climate
Volume28
Issue number20
DOIs
StatePublished - 2015

Fingerprint

Rossby wave
atmospheric circulation
teleconnection
ocean basin
winter
ocean
warming
standing wave
wave dispersion
wind shear
vorticity
train
simulation
Southern Hemisphere
sea surface temperature
cooling
climate change
Antarctica
climate
sea

Keywords

  • Atm/Ocean Structure/Phenomena
  • Atmosphere-ocean interaction
  • Atmospheric
  • Circulation/Dynamics
  • Decadal variability
  • Polar lows
  • Rossby waves
  • Teleconnections
  • Variability
  • Waves

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Rossby waves mediate impacts of tropical oceans on west Antarctic atmospheric circulation in austral winter. / Li, Xichen; Holland, David M.; Gerber, Edwin P.; Yoo, Changhyun.

In: Journal of Climate, Vol. 28, No. 20, 2015, p. 8151-8164.

Research output: Contribution to journalArticle

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